1. Technical Field
The present invention relates to a dimming circuit including an active dimmer for applying input power Vin to an amplification module or an error compensation module, an amplification module for amplifying the output current of the active dimmer, and an error compensation module for correcting an error or distortion of the amplification module, wherein the amplification module and the error compensation module are connected in a feedback form.
2. Description of the Related Art
A light-emitting diode (LED) is a kind of semiconductor device for converting electric energy into light. An LED has advantages of low consumption power, a semi-permanent lifespan, a fast response speed, safety, and an eco-friendly property compared to existing light sources, such as a fluorescent lamp and an incandescent. In particular, an LED lamp device can perform various productions through control of the blinking sequence of a plurality of arranged LEDs, light-emitting color, and brightness.
A lot of research is being carried out in order to replace the conventional light sources with LEDs. An LED tends to be increasingly used as the light sources of lamp devices, such as various lamps used indoors, liquid crystal display devices, electric bulletin boards, and streetlamps. In particular, an LED is used as common lamps for indoor interior, a stage lamp for producing a specific atmosphere, an advertising lamp, and a view lamp.
A lamp is an elapse lamp and may be installed in an outer wall of a building, a park, a streetlamp, a bridge rail or a theater. The size and application system of a lamp may be different depending on use, a target or a location to which the lamp device is applied. That is, lamps for an outer wall of a building are installed in an outer wall of a building in a belt form and are used to simply display a single color or a combined color through a blinking function. Lamps for a park, a streetlamp or a bridge rail are irregularly installed depending on the shape of the subject and are used to change their blinking or colors.
An LED lamp has propagated rapidly due to a long lifespan and high efficiency compared to conventional lamps. A dimmer capable of changing luminous intensity in response to a change of weather and over time has been commercialized. The type of method for controlling such a dimmer may be divided into wireless communication and wired communication. In particular, wireless communication is used, brightness is controlled by adjusting a Dim (+−) line within each driver.
In particular, the dimming function of an LED lamp is widely used in various fields because it can be conveniently applied and has eco-friendly advantages. A 0-10V dimming method is used most widely. In this case, the 0-10V dimming method is divided into a passive method for controlling dimming light using a variable resistor and active method for controlling dimming light using a sink current. The active method is widely used because it has more excellent compatibility.
If a plurality of lamp devices is driven, however, a sink current for one lamp device is about 2 mA, but a maximum output current of an operational amplifier is about 10 mA. Accordingly, the active method has a disadvantage in that only a maximum of five lamp devices can be driven. Various researches are being carried out on a dimming circuit capable of driving a plurality of lamp devices at the same time or individually.